« As expected, the success rate with IPv6-only domain names (around two thirds) is much lower than with "mixed" domain names. We are not yet ready to switch off IPv4. If you serve a domain name only on IPv6 name servers, you will get less traffic (and probably less spam, too).

Nevertheless, one can notice that the success rate in resolving these IPv6-only domain names is higher than the number of probes having IPv6 connectivity. So, we can say that the typical DNS resolver is more IPv6-enabled than its clients. »